In general, a lead storage battery is employed as a driving source of a motor in an automated guided vehicle used in a factory or a depot. In the technique discussed in JP 1991-37967 A, an automated guided vehicle is disclosed, which is used after a battery of the automated guided vehicle is fully charged in a charging station provided in a factory or a depot. In addition, in the technique discussed in JP 2007-74800 A, a lithium ion battery that can be partially charged instead of the full charging is used as a battery of the automated guided vehicle.
In the automated guided vehicle discussed in JP 2007-74800 A, the automated guided vehicle travels by virtue of electric power of the lithium ion battery. The battery of the automated guided vehicle is charged in the charging station included in a battery charge and discharge management system. In the charging station, the charging operation starts when a remaining capacity of the battery reaches a charging start capacity. The charging operation stops when the remaining capacity of the battery reaches a charging stop capacity.
In an automated guided vehicle that uses a lithium ion battery as a battery, a battery unit is configured by integrating and housing a battery, a control panel such as a charge and discharge monitor that monitors a charge and discharge condition of the battery, and other electric components in a battery casing. In such a battery unit, dew condensation may occur on an inner surface of the battery casing depending on a weather condition such as humidity or temperature inside the battery casing. An electric failure may occur if a droplet of dew flows down along the inner surface of the battery casing and is attached on the battery, the electric component, and the like.